Fuel ignition system



May l13, 1952 W, G, SEE 2,596,729

FUEL IGNITION SYSTEM wc.) mW-l in 20/ QQ, 0010/01/ l 5U ,j/MZZ/e/ZZH.Mie/1 (U/y@ Se@ May 13, 1952 w. G. SEE 2,596,729

FUEL IGNITION SYSTEM Filed Nov. 5, 1947 2 SHEETS--SHEE'I' 2 NoTE; THEswlTcHl-:s 49,52,5s,s|as2 ARE NoRMALLY oPEN. THE swlTcH 57 ls NoRMALLYcLosED.

NOTE: THE SWITCHES 52 8 57 ARE SLOW OR TIME DELAY (T.D) ACTION SWITCHES.

tion above the level of the liquid I3. The lower ends of the members 2Iand 22 may be held in concentric relationship the one with respect tothe other, and with respect to the outer member I5, by means of spacingcollars 24 applied at the terminal ends of the members'2I and 22, whichspacing collars allow for the free flow of fuel and air, respectively,through the concentric passageways I8 and 2G, into the member I5 belowthe spacing collars for delivery thence to the burner I2, through thecasing I5.

The fitting 23, as shown more particularly in Fig. 4 of the drawings,may provide for the threaded or welded connection of laterally extendingconduits I8 and 20', respectively for delivering fuel and air to theconcentric channels I8 and 2U. Y

rlhe fitting 23 provides for the connection of the central channel I9,in an axial direction with v a chamber 25 formed at the end of thefitting 23 as by securing thereto, or integrally forming thereon, apreferably sleeve-like member 26, said member providing, as shown moreparticularly in Fig. 3, for the connection of the chamber 25 with alaterally extending pilot air supply pipev 21. The sleeve-like member 26and the fitting 23 may,of course, be formed as separate elements securedtogether in any convenient or suitable fashion as by bolts, although,for the sake of convenience, it is preferable to form them as anintegral unit. A preferably removable cover 28 may also be provided forclosing the chamber 25, and said cover may provide an inlet chamber 29connecting with a pilot fuel supply conduit 39 and communicating, as bymeans of a pipe 3l, through the chamber 25 with the interior of thechannel i3 substantially below the chamber 25.

The principal elements of the burner thus com# prise the outerpassageway I8 through which the main supply of fuel may be introduced tothe purpose may comprise approximately 85% silicon carbide and 15%elemental silicon, by weight, the silicon carbide component beingpreferably in the form of a continuous reticular skeleton, in which theunit crystals are minute, uniformly distributed, and of cubic formation.

The lsilicon component preferably comprises elemental silicon whichcompletely fills the interstices of the silicon carbide skeleton. Suchmaterial mayconveniently be produced in bars or rods of desired lengthand sectional configuration. Such bars will withstand exceedingly highoperating temperatures without disintegration or the bar, at itsopposite ends, to a pair of support the burner, the intermediatepassageway 20 through which the main supply of air may be introduced,the pipe 3I through whicha supply of pilot fuel may be introduced intothe central conduit I9 in the vicinity of the igniter I1, and thereburned in air supplied through the conduit 21 and chamber 25 into theconduit I9. Upon ignition, the pilot fuel will burn at .the lower end ofthe conduit I9 in position to ignite main fuel within the outer memberI5 below the lower end of the central channel I9. In submergedcombustion equipment, it should be understood that the air and fuel mustbe supplied at pressures great enough to overcome the head pressure ofliquid at the burner; and any suitable apparatus may be utilized for thepurpose of delivering fuel and air at required pressures and volumetricrates through the conduits I8', 2U', 21 and 39. To this end any suitableor preferred air and fuel delivery devices may be employed, suchdelivery apparatus, where gaseous fuel is involved, preferablycomprising means for supplying the fuel at desired pressure to theconduits i8 and 39, including electrically operated control valves inthe fuel supply pipes I8 and 30, air supply being conveniently providedas by means of electrically controllable blower equipment and air iiowregulating valves in the air supply conduits 23 and 21.

The igniter I1 preferably comprises a bar or rod 32 of material having anegative temperature coefficient of electrical resistance, the bar 32,to this end, preferably comp-rising a carbon compound suoh as siliconcarbide. A bar suitable for stems 33 of electrical conducting material.These stems in turn may be mounted within and insulated from the fitting23 in any suitable or preferred fashion. As shown, the fitting 23provides an annular seat 34, facing into the chamber 25 at the end ofthe central channel I9 where said channel connects with the chamber 25.A mounting member, as shown more particularly in Fig. 6, is provided forsupporting the stems 33 on the fitting 23. This mounting member orholder 35 may comprise any suitable preferably heat resistant electricalinsulating material, such as porcelain, forming a central hub 36,defining an axial channel 31 and radially extending iianges 38projecting outwardly of the hub 36. The outer edges of the iianges 38are adapted to lit snugly within the walls dening the channel I9, andsaid flanges at their upper portions are formed with projecting lugs 39adapted to t snugly within the walls of the chamber 25 and to rest uponthe annular seat 34 whereby to support the member 35 within the chamberconnected end of the channel I9. On one side of the channel 31 and onopposite sides of a lug 39 thereof, the holder comprises a body portion40 having an outer surface adapted to snugly interiit with the innersurface of the walls defining the channel I9. This body portion isprovided with a pair of axial channels 4I adapted to snugly receive andvhold the stems 33 and thus support the same in the fitting 23. The stems33 have ends projecting upwardly of the holder 35 within the chamber 25,said ends being fitted with terminal means 42 adapted Yto electricallyconnect the posts 33 with electrical conductors 43 which may extendthence outwardly of the chamber 25, as through the pilot air conduit 21.The conduit 21, outwardly of the housing member 26, may be provided withinsulated air-tight outlets through which the conductors 43 may extendoutwardly of the pipe 21 for connection with any suitable source ofigniter actuating electrical power.

vIt will be seen that the central channel 31 of the holder 35 mayreceive the fuel inlet pipe 3i therethrough to thereby aid in supportingthe pipe 3I in axially centered position within the conduit I9, wherebypilot fuel may be delivered in said conduitV below the holder 35. TheWebbed lsource, -to a selected maximum value.

or spider'conguration'of the vholder outwardly of the central hubVthereofV affords free pas" sage for the. deliveryjof pilot air into theconduit l I9 from .the chamber 25.

Theigniter: may be operated by ,connecting/the.'

conductors 43 witha suitable source of electrical' igniter energizingApower. Because of its negative temperature coeflicient of resistance,the igniterA element 32 operates as an automatic rheostat in that it'is' cold .and offers relatively high resistance .to current flow, whenthe actuating,

element, the resulting current now therethrough' increases progressivelyand proportionately'as the elementbecomes heated to ignitingtemperature, withconsequentdecrease in the resistance of the increases.due :to electrical current flowv element.. This characteristic enablesthe igniter,..

aswell as the. fuel. supply means to the burner,.

to be controlled in positive fashion by an exceedinglyv simpleelectrical control system, taking advantage of lthe aforesaid negativetemperature. coeiiicient.ofresistance. of the igniter element.

As shown more particularly in Fig. 7 ofthe..

drawings, the. igniter element 32 may be energized from a transformer44, the secondary orl output vwinding ofv which is connected with theconductors 43, the primary winding of said transformer being energizedfrom any suitable source of electrical power 45 .through suitableprotective equipment 46v and a preferably manually operable controlswitch 41 whereby the transformer 44 may be energized from the powersource 45 upcn closure of the switch means 41. Since the igniter elementhas a negative resistance coeicient, said transformer 44, if desired, asa safety measure, may have impedance characteristics whereby to limitthe current flow thereto, from the power As the igniter element 32becomes heated toward ignition temperature, current flow in the primarycircuit of the transformer 44 will materially increase from the minimumvalue, determined by the resistance of the element 32 when cold, to apredeterminable current ow value when the element 32 reaches itsignition temperature. Accordingly, theoperating coil 48 of a relayswitch, having normally open switch means 49, may be interconnected inthe energizing circuit cf the,

transformer 44 to cause closure of the switch means 49 as the element 32reaches or exceeds its .ignition temperature. The switch 49 may beinterconnected in series with the operating solenoid 5| of a fuel flowcontrol device such as a valve 5|' disposed in the pilot fuel conduit 30to.

flowcontrol device such as a valve trdisposed.

inthe lmain'fuel supply conduit {8to actuate. the .same for the-delivery of fuel upon closure ofthe switch 52'. Air blower orcompressor means, or4 both; ma-y be `employed' to supply air or fuelalso be\- energized for n'operationunder the control Upon closurercftheswitch-H; thev ignition element 32may,bebrought` to its ignitingtempera'- turefand:iairand:pilotfuelA may be deliveredv through theconduits ^21 'and30 as soon as the igniterY element" has reached `itsigniting temperature, whereby la pilotiiiamev may-.be established atthe-lowerfendl-of the/central channelt I9 of the burnerfmy Afteral timedelay vsuflicient `to assure` th'efestablishment of the pilotv flame,ymain lfuel and. air may be delivered'through'the conduits I3"V and'i2llto'rthe 'burner mechanism, upon closureof the'switch52, the main fuelthus supplied Jbeing. ignited by gthe previously establishedpilo'tiiam'e'forv combustionvatV the burnerV I 2 Thercontrol'isystemshown'inl'ig.r 'I is exceedingly -simple vand* 'adapted'fo'r manualoperation under. theicontrolofthe switch 41. The pilot. and jmainrburnerlames, having been established in the manner'described, willcontinue in operation.

barring `fai-lurenofthe. fuel;y air and electrical power'supplyruntil'the switch.41 is opened.I As

soonastheswitch41' isopened, `orupon failure of the'y 'electrical power'supplyfthez coil48 will be.-

come nei-energizedfthe 'switches l49. .and 52 will.vopen',"thereby^stopping the delivery of. main 'and pilot fuel and "air:to the combustion apparatus.'

Fig; *8, iiniradditionto the equipment shown in Fig.;V 7,- includes`ladditional automatic switch means'ffor disabling 'the igniter control.circuitV after establishment of the pilot flame and the ignition of'main'burner' fuel delivered through the conduit I8', whereby, aftercombustion has 30-and such air blower or compressor means may' been'establishedtheigniter may be` rendered inoperative withoutshutting offtheA supply of .pilot or main-fuel.- l Totheseendsa relay switchmechanism^"54, havingn an operating'coil 55, is provided,saicl'operating 'coil 'being connected in parallel relationship-withrespect to. the fuel control-solenoid'i53', under the control of thetime delay closing switch52`. The switch 54 includes normallyopen-switch `means v56 and normally closed time delay opening switchmeans 51.. The time delay opening switch means`51 is connected in theoperating circuit of the relay switch coil 48 and ofthe transformer 44,while the normally open switch 56 is connected in a circuit to control'the operating solenoid 58 of a relay switch 59, inorder to'actuate saidswitch'for the closure of its normally 'open.switchmeans 6| and 62whenever the coil 58 is energized in .response to closureof'theswitch56. The switches 5| and 62. respectively, areinterconnected in parallelrelationship with. the switches 49 and 52, whereby,

to maintain,'in energized condition, the fuel and f air supply means 5|and 53 upon the opening of the establishment of .the combustion ,of.main

fuel'at the burner, the time delay opening switch 51 may operatetodisable the igniter energizing transformeraswellas the solenoid 48..Thereyuponthe switches 49' and 52will` open, but burner operation willbe maintained thereafter by the switches 6| and 62, which remain inclosed position, thereby maintaining the solenoids I and 53 energized tocontinue the fuel supply to the burner; and the switch 62 also maintainsenergy in the switch operating coil 55 to hold the switch 56 closed andthe switch 51 open. The burner is thus maintained in operation, barringfailure of the fuel, air, and electrical power supply, so long as theswitch 41 remains closed. By opening the switch 41, of course, theentire apparatus will be restored to starting condition.

Obviously, numerous modifications may be made in the control system inorder to accomplish refinements in the control of the air and fuelsupply, as by the addition of control relay switches and other controlequipment. Essentially, however, the present invention provides benefitsowing from the utilization of the ignition element 32 having a negativetemperature coefficient of resistance whereby-operation of the controlsystem is accomplished in response to increased current ow in theenergizing circuit of the transformer 45 and of the switch actuatingcoil 48. It is desirable, of course, and especially in the manual systemas shown in Fig. 7, toprovide for limiting current flow to the ignitionelement 32, to a predetermined value appreciably in excess of thatrequired to heat the ignition element to its igniting temperature. Tothis end the transformer 44 may conveniently comprise a current limitingtransformer selected for the purpose of limiting at a desired value thecurrent flow to the element 32.

It is thought that the invention and its numerous attendant advantageswill be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several parts without departing from the spirit orscope of the invention, or sacrificing any of its attendant advantages,the form herein disclosed being a preferred embodiment for the purposeof illustrating the invention.

The invention is hereby claimed as follows:

l. The combination, with fuel burning apparatus having associated pilotfuel delivery means and main fuel delivery means, of pilot fuel ignitionmeans comprising an electrically operable igniter element having anegative temperature coefficient of electrical resistance, means formounting said element in position to ignite said pilot fuel upondelivery thereof in said fuel burning apparatus, and an electricalsystem for actuating said igniter element and for controlling thedelivery of main and pilot fuel to said burner apparatus comprising apilot solenoid valve means for controlling pilot fuel, a main solenoidfor controlling main fuel, means for energizing said igniter, a currentresponsive relay, responsive to current 110W to said igniter element,including pilot switch means for controlling said pilot solenoid whencurrent flow to said igniter element reaches a predetermined value andmain fuel switch means operable to control said main solenoid after atime delay interval following operation of said pilot switch means, andrelay switch means operable by said current responsive relay formaintaining said pilot and main solenoids ,in operation and fordisabling said igniter element and said current responsive relay after apredetermined time delay following operation of said current responsiverelay.

2. The combination, with fuel burning apparatus having associated pilotfuel delivery means i and main fuel delivery means, of pilot fuelignition means comprising an electrically operable igniter elementhaving a negative temperature coeflicient of electrical resistance,means for mounting said element in position to ignite said pilot fuelupon delivery thereof in said fuel burning apparatus, and an electricalsystem for actuating said igniter element and for controlling thedelivery of main and pilot fuel to said burner apparatus comprising apilot solenoid for controlling pilot fuel, a main solenoid valve meansfor controlling main fuel, means for energizing said igniter, a currentresponsive relay, responsive to current ow to said igniter element,including pilot switch means for controlling said pilot solenoid whencurrent ow to said igniter element reaches a predetermined value andmain fuel switch means operable to control said main solenoid after atime delay interval following operation of said pilot switch means.

3. The combination, with fuel burning apparatus having associated fueldelivery means, of an electrically operable igniter element having anegative temperature coeflcient of electrical resistance, disposed inposition to ignite fuel upon delivery thereof in said fuel burningapparatus, and an electrical system for actuating said igniter elementand for controlling the de-v livery of fuel to said burner apparatuscomprising a solenoid valve means for controlling the delivery of fuel,means for energizing said igniter, a current responsive relay,responsive to current flow to said igniter element, including switchmeans for controlling said solenoid when current flow to said igniterelement reaches a predetermined Value, and holding relay switch meansoperable by said current responsive relay for maintaining said solenoidin operation and for disabling said igniter element and said currentresponsive relay, after a predetermined time delay following operationof said current responsive relay.

4. The combination, with submerged combustion fuel burning apparatushaving associated pilot fuel delivery means and main fuel deliverymeans, of an electrically operable igniter element for said pilot fuelhaving a negative temperature coefficient of electrical resistance,disposed in position to ignite pilot fuel upon delivery thereof in saidfuel burning apparatus, and an electrical system for actuating saidigniter element and for controlling the delivery of main and pilot fuelto said burner apparatus comprising solenoids for controlling thedelivery of fuel, current limiting means for energizing said igniteryanda current responsive relay, responsive to current flow to said igniterelement, including switch means for controlling said solenoids whencurrent flow to said igniter element reaches a predetermined value.

5. The combination, with fuel burning apparatus having associated pilotfuel delivery means and main fuel delivery means, of an electricallyoperable igniter element for said pilot fuel having a negativetemperature coefficient of electrical resistance, disposed in positionto ignite pilot fuel upon delivery thereof in said fuel burningapparatus, and an electrical system for actuating said igniter elementand for controlling the delivery of main and pilot fuel to said burnerapparatus comprising solenoids for controlling the delivery of fuel,means for energizing said igniter, and a current responsive relay,responsive to current fiow to said igniter element, including switchmeans for controlling said sole- 9 noids when current flow to saidigniter element reaches a predetermined value.

6. Fuel burning apparatus comprising means forming concentric channelsfor the delivery oi fuel and air to a combustion chamber, includingmeans forming a delivery channel extending from a receiving chamber tosaid combustion chamber, and a pipe extending axially of and having anend opening Within said delivery channel, a spider-like frame ofelectrical insulating material mounted in said delivery channel at saidreceiving chamber, said frame forming a central bushing for mountingsaid pipe Within said delivery channel, said frame providing spacedsupport bushings ofrset radially with respect to said central bushing,support stems of electrical conducting material mounted in said supportbushings, an electrically operable igniter element mounted on andelectrically connected with said support stems, within said deliverychannel and adjacent the end of said pipe.

7. Fuel burning apparatus comprising means forming concentric channelsfor the delivery of fuel and air to a combustion chamber, includingmeans forming a delivery channel extending from a receiving chamber tosaid combustion chamber, and a pipe extending axially of and having anend opening within said delivery channel, a spider-like frame ofelectrical insulating material mounted in said delivery channel at saidreceiving chamber, said frame forming a central bushing for mountingsaid pipe within said delivery channel, said frame providing 10 spacedsupport bushings offset'radially with respect to said central bushing,support stems of electrical conducting material mounted in said supportbushings, an electrically operable igniter element mounted on andelectrically connected with said support stems, within said deliverychannel and adjacent the end of said pipe, a laterally opening supplyconduit to said receiving chamber, and conductors for electricallyenergizing said igniter element electrically connected with said supportstems Within said receiving chamber and extending outwardly thereofthrough said supply conduit.

WALTER GEORGE SEE.

REFERENCES oi'rnn The following references are of record in the file oithis patent:

UNITED STATES PATENTS Number Name Date 1,372,330 Bailey et al Mar. 22,1921 1,495,855 Little May 27, 1924 1,940,127 Herthnecli Dec. 19, 19332,068,425 McCabe Jan. 19, 1937 2,095,253 Heyroth Oct. 12, 1937 2,291,805Denison Aug. 4, 1942 2,296,686 Ragan Sept. 22, 1942 2,329,883 Eskin etal. Sept. 21, 1943 2,340,734 Clark ,Feb. 1, 1944 2,385,699 Fox Aug. 25,1945 2,408,047 Cunningham Aug. 24, 1946 2.432.942 See et al Dec. 16,1947

